U.S. patent number 11,370,624 [Application Number 16/987,508] was granted by the patent office on 2022-06-28 for image forming apparatus.
This patent grant is currently assigned to Canon Kabushiki Kaisha. The grantee listed for this patent is CANON KABUSHIKI KAISHA. Invention is credited to Yuki Uchida.
United States Patent |
11,370,624 |
Uchida |
June 28, 2022 |
Image forming apparatus
Abstract
An image forming apparatus has: a cassette which stores a sheet;
a pickup roller which picks up the sheet inside the cassette; a
feed roller which feeds the sheet picked up by the pickup roller
toward an image forming portion; and a retard roller which is
pressed against the feed roller and forms a separation nip. In
addition, the image forming apparatus has a conveying guide which
guides the sheet picked up by the pickup roller to the separation
nip. A first guide member of the conveying guide is configured to
be slidable in a drawing direction when the feed roller is
replaced, and the conveying guide is formed of a material whose
property of light transmittance of light having a wavelength of 360
nm to 420 nm is 80% or more. The feed roller is detachable from the
one end of a shaft in a state in which the cassette is drawn out
along the rail and the conveying guide is slid in the drawing
direction.
Inventors: |
Uchida; Yuki (Kashiwa,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
CANON KABUSHIKI KAISHA |
Tokyo |
N/A |
JP |
|
|
Assignee: |
Canon Kabushiki Kaisha (Tokyo,
JP)
|
Family
ID: |
1000006397562 |
Appl.
No.: |
16/987,508 |
Filed: |
August 7, 2020 |
Prior Publication Data
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Document
Identifier |
Publication Date |
|
US 20210070567 A1 |
Mar 11, 2021 |
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Foreign Application Priority Data
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Sep 5, 2019 [JP] |
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JP2019-161729 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65H
3/0676 (20130101); B65H 3/66 (20130101); B65H
3/0638 (20130101); B65H 1/266 (20130101); B65H
2402/32 (20130101); B65H 2401/115 (20130101); B65H
2401/222 (20130101); B65H 2601/324 (20130101) |
Current International
Class: |
B65H
3/66 (20060101); B65H 1/26 (20060101); B65H
3/06 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2007-126228 |
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May 2007 |
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JP |
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2015-221707 |
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Dec 2015 |
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JP |
|
Primary Examiner: Gokhale; Prasad V
Attorney, Agent or Firm: Venable LLP
Claims
What is claimed is:
1. An image forming apparatus comprising: an image forming portion
which forms an image on a sheet; a cassette which stores a sheet; a
pickup roller which picks up the sheet inside the cassette; a feed
roller which feeds the sheet picked up by the pickup roller toward
the image forming portion and is attached to one end of a shaft; a
separation member which is provided in a position facing the feed
roller, forms a separation nip by being pressed against the feed
roller, and separates a plurality of sheets picked up by the pickup
roller one by one at the separation nip; a rail which supports the
cassette and along which the cassette is drawn in a drawing
direction orthogonal to a conveying direction; and a conveying
guide which guides the sheet picked up by the pickup roller to the
separation nip, the conveying guide including: a first guide member
which is located above the separation nip in a vertical direction
and is located further downstream of the cassette in a drawing
direction than the feed roller; a second guide member which is
located above the separation nip in the vertical direction and is
located further upstream of the cassette in the drawing direction
than the feed roller; and a third guide member which is located
below the separation nip in the vertical direction and is located
in a position where the third guide member overlaps with the feed
roller in the drawing direction, the first guide member being
configured to be slidable in the drawing direction when the feed
roller is detached from the shaft and being formed of a material
whose property of light transmittance of light having a wavelength
of 360 nm to 420 nm is 80% or more, each of the second and third
guide members being formed of a material whose light transmittance
of the light having the wavelength of 360 nm to 420 nm is less than
80%, the feed roller being detachable from the one end of the shaft
in a state in which the cassette is drawn out along the rail and
the first guide member is slid in the drawing direction.
2. The image forming apparatus according to claim 1, further
comprising a feeding frame which supports the first guide member in
a slidable manner, wherein the feeding frame is formed of a
material whose light transmittance of the light having the
wavelength of 360 nm to 420 nm is less than 80%.
3. The image forming apparatus according to claim 1, wherein the
first guide member has a handle portion which is operated by a user
when the feed roller is replaced and a portion which is rubbed by
the conveyed sheet, the portion being rubbed by the conveyed sheet
is formed of a resin material whose property of light transmittance
of the light having the wavelength of 360 nm to 420 nm is 80% or
more, and the handle portion is formed of a material whose light
transmittance of the light having the wavelength of 360 nm to 420
nm is less than 80%.
4. The image forming apparatus according to claim 1, wherein the
pickup roller is supported by the one end of the shaft in a
detachably attachable manner and is detachable from the side of the
one end of the shaft in the state in which the cassette is drawn
out along the rail and the first guide member is slid in the
drawing direction.
5. The image forming apparatus according to claim 1, wherein the
feed roller includes a core portion which is formed of resin and an
outer peripheral portion which is wound around the core portion, is
formed of a rubber material, abuts against the sheet, and has
chromatic color.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to an image forming apparatus which
forms an image on a sheet fed from a cassette.
Description of the Related Art
Conventionally, on image forming apparatuses such as printers,
facsimile apparatuses, and copying machines, sheet feeding devices,
which feed stacked sheets to image forming portions are mounted in
general. Each of the sheet feeding devices is configured such that
stacked sheets are fed by a pickup roller and are conveyed in such
a way as to separate the sheets one by one between a feed roller,
which rotates in the same direction as a sheet feeding direction,
and a retard roller, which is pressed against the feed roller by a
spring.
However, when in each of the above-mentioned sheet feeding devices,
abrasion of the rollers develop due to enduring, failure in
conveyance of the sheets is caused. Therefore, as disclosed in each
of Japanese Patent Laid-Open No. 2015-221707 and Japanese Patent
Laid-Open No. 2007-126228, the rollers are configured to be
replaceable.
In Japanese Patent Laid-Open No. 2015-221707, a conveying guide
which guides a sheet conveyed by a conveying roller is provided to
be movable in an axial direction of a driving shaft of the
conveying roller, and the conveying roller is accessible by this
movement of the conveying guide in the axial direction.
In Japanese Patent Laid-Open No. 2007-126228, a guiding plate which
guides conveyance of a sheet is supported by a device main body in
an openable and closable manner, and by opening the guiding plate,
a working space for attaching and detaching a sheet feeding roller
to and from a driving shaft is exposed.
In a case of a configuration in which upon replacing the roller, a
cassette which stores sheets is drawn out from an image forming
apparatus and the roller is visually recognized from a space formed
by drawing out the cassette, it is difficult to find the roller
since the roller is hidden by the conveying guide. This is because
it is required to make the conveying guide approach to a nip
position of the rollers. In general, the larger a distance between
the nip position of the rollers and a sheet guiding surface of the
conveying guide is, the more easily failure in feeding is caused
when a leading edge of a sheet is brought in contact with a
peripheral surface of the roller. Therefore, the distance between
the nip position of the rollers and the sheet guiding surface of
the conveying guide is designed as small as possible. In positional
relationship therebetween, only a slight range of the roller, which
comes out of the conveying guide, can be visually recognized from
the space formed by detaching the cassette housing the sheets as
described above.
SUMMARY OF THE INVENTION
The present invention provides a unit which allows a roller
targeted for replacement to be easily visually recognized.
An image forming apparatus according to the present invention
includes:
an image forming portion which forms an image on a sheet;
a cassette which stores a sheet;
a pickup roller which picks up the sheet inside the cassette;
a feed roller which feeds the sheet picked up by the pickup roller
toward the image forming portion and is attached to one end of a
shaft;
a separation member which is provided in a position facing the feed
roller, forms a separation nip by being pressed against the feed
roller, and separates a plurality of sheets picked up by the pickup
roller one by one at the separation nip;
a rail which supports the cassette and along which the cassette is
drawn in a drawing direction orthogonal to a conveying direction;
and
a conveying guide which guides the sheet picked up by the pickup
roller to the separation nip,
the conveying guide including: a first guide member which is
located above the separation nip in a vertical direction and is
located further downstream of the cassette in a drawing direction
than the feed roller; a second guide member which is located above
the separation nip in the vertical direction and is located further
upstream of the cassette in the drawing direction than the feed
roller; and a third guide member which is located below the
separation nip in the vertical direction and is located in a
position where the third guide member overlaps with the feed roller
in the drawing direction,
the first guide member being configured to be slidable in the
drawing direction when the feed roller is detached from the shaft
and being formed of a material whose property of light
transmittance of light having a wavelength of 360 nm to 420 nm is
80% or more,
each of the second and third guide members being formed of a
material whose light transmittance of the light having the
wavelength of 360 nm to 420 nm is less than 80%,
the feed roller being detachable from the one end of the shaft in a
state in which the cassette is drawn out along the rail and the
first guide member is slid in the drawing direction.
Further features of the present invention will become apparent from
the following description of exemplary embodiments with reference
to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic cross-sectional view showing an image forming
apparatus;
FIG. 2 is a schematic view showing a sheet feeding device;
FIG. 3 is a perspective view showing a configuration of a feeding
unit in a sheet feeding portion;
FIG. 4 is a perspective view showing a configuration of the feeding
unit in the sheet feeding portion;
FIG. 5 is a top view showing the sheet feeding device;
FIG. 6 is a top view showing the sheet feeding device;
FIG. 7 is a top view showing the sheet feeding device;
FIG. 8 is a view showing a state in which a storage is supported in
the image forming apparatus;
FIG. 9 is a perspective view showing a configuration of the
vicinity of rollers in the feeding unit;
FIGS. 10A and 10B are cross-sectional views showing a feeding
roller;
FIGS. 11A, 11B, and 11C are views showing a state of the storage
and the feeding unit, viewed from an arrow C direction shown in
FIG. 2;
FIG. 12 is a perspective view showing positional relationship of a
conveying guide and a feeding portion frame; and
FIG. 13 is a view showing the vicinity of the rollers in the
feeding unit, viewed from a space shown in FIG. 11B.
DESCRIPTION OF THE EMBODIMENTS
Hereinafter, with reference to the attached drawings, an exemplary
embodiment of the present invention will be described in detail in
an illustrative manner. However, dimensions, materials, shapes, and
relative arrangement of components described in the below
embodiment are to be appropriately modified based on a
configuration of an apparatus and a variety of conditions to which
the present invention is applied and are not intended to limit the
present invention thereto merely.
[Image Forming Apparatus]
With reference to FIG. 1, one example of an image forming apparatus
according to the present embodiment will be described. Here, as the
one example of the image forming apparatus, a color image forming
apparatus of an intermediate transfer system using an
electrophotographic system is illustrated. FIG. 1 is a
cross-sectional view of the image forming apparatus including a
sheet feeding device according to the present embodiment.
The image forming apparatus 200 includes: an image forming portion
20 which forms an image on a sheet; a fixing portion 40 which fixes
the image on the sheet; a sheet discharging portion 50 which
discharges the sheet on which the image is fixed; and sheet feeding
portions 100 and 60, each of which feeds the sheet to the image
forming portion 20. As the sheet feeding portions, a sheet feeding
portion 100 which is located in a lower portion of an apparatus
main body 200A and a multi-feeding portion 60 which is located in
one of side portions (a right side portion in FIG. 1) of the
apparatus main body 200A are included. The sheet feeding portion
100 will be described in detail later.
The image forming portion 20 is an image forming portion of the
so-called 4-drum full-color system, which includes a laser scanner
70, four process cartridges P, and an intermediate transfer portion
30. These process cartridges P form toner images having respective
colors of yellow (Y), magenta (M), cyan (C), and black (K). The
process cartridges P (PY, PM, PC, and PK) include photoconductor
drums 21 (21Y, 21M, 21C, and 21K), charging devices 22 (22Y 22M,
22C, and 22K), and development devices 23 (23Y, 23M, 23C, and 23K),
and a cleaning device, not shown. It is to be noted that the
process cartridges P have the same configurations as one another
except that toner colors thereof are different from one
another.
The intermediate transfer portion 30 has an intermediate transfer
belt 31 which is wound on a driving roller 32, a driven roller 33,
and a tension roller 34. The intermediate transfer belt 31 is
located above the four process cartridges P (PY, PM, PC, and PK).
The intermediate transfer belt 31 is located in such a way as to
contact the photoconductor drums 21 of the process cartridges P and
is rotatably driven in a counterclockwise direction by the driving
roller 32 driven by a driving portion, not shown. The intermediate
transfer portion 30 includes primary transfer rollers 35 (35Y, 35M,
35C, and 35K) in positions facing the photoconductor drums 21, the
primary transfer rollers 35 abutting against an inner peripheral
surface of the intermediate transfer belt 31, and as nip portions
each between the intermediate transfer belt 31 and the
photoconductor drums 21, primary transfer portions are formed. In
addition, the image forming portion 20 includes a secondary
transfer roller 36 in a position facing the driving roller 32, the
secondary transfer roller 36 abutting against an outer peripheral
surface of the intermediate transfer belt 31. As a nip portion
between this secondary transfer roller 36 and the intermediate
transfer belt 31, a secondary transfer portion where a toner image
carried on the intermediate transfer belt 31 is transferred onto
the sheet is formed.
In the process cartridges P configured as described above, on
surfaces of the photoconductor drums 21, an electrostatic latent
image is drawn by the laser scanner 70 and thereafter, toner is
supplied from each of the development devices 23, thereby forming
toner images charged with negative polarity and having the
respective colors. A transfer bias voltage of positive polarity is
applied to each of the primary transfer rollers 35 and on the
primary transfer portions, these toner images are thereby
sequentially multiple-transferred (primary-transferred) to the
intermediate transfer belt 31, thereby forming a full-color toner
image on the intermediate transfer belt 31. In parallel with the
above-described processes of forming the toner images, the sheet
fed from the sheet feeding portion 100 or the multi-feeding portion
60 is conveyed toward a pair of registration rollers 12 by a pair
of conveying rollers 11, and skew feeding of the sheet is corrected
by this pair of registration rollers 12. At timing coinciding with
timing at which the full-color toner image formed on the
intermediate transfer belt 31 is transferred, the pair of
registration rollers 12 convey the sheet S to the secondary
transfer portion. A transfer bias voltage of positive polarity is
applied to the secondary transfer roller 36, whereby the toner
image carried on the intermediate transfer belt 31 is
secondary-transferred onto the sheet on the secondary transfer
portion. The sheet S onto which the toner image is transferred is
heated and pressurized by a pair of fixing rollers 41 in the fixing
portion 40 and a color image is fixed onto the sheet. The sheet S
having the image fixed thereon is discharged to a discharge tray 51
by a pair of discharging rollers 52 in the sheet discharging
portion 50 located downstream from the fixing portion and is
stacked. It is to be noted that an arrow A in FIG. 1 indicates a
conveyance path along which the sheet fed from the sheet feeding
portion 100 travels up to when the sheet is discharged to the
discharge tray 51 of the sheet discharging portion 50.
In addition, when an irregular sized sheet is used, the irregular
sized sheet is fed by the multi-feeding portion 60. Specifically,
the irregular sized sheet is set to a multi-tray 61. The sheet set
to the multi-tray 61 is fed by multi-feeding rollers 62 and
thereafter, is conveyed to the pair of conveying rollers 11,
whereby an image is formed thereonto by conducting the same
processes as those in a case in which the sheet is fed from the
sheet feeding portion 100, and the irregular sized sheet is
discharged to the discharge tray 51.
[Sheet Feeding Portion]
With reference to FIGS. 1, 2, 3, 4, and 12, a sheet feeding portion
as one example of a sheet feeding device according to the present
embodiment will be described. FIG. 2 is a schematic explanatory
diagram showing the sheet feeding portion according to the present
embodiment. FIGS. 3 and 4 are perspective views showing a
configuration of a feeding unit in the sheet feeding portion. FIG.
12 is a perspective view showing positional relationship of a
conveying guide and a frame of the feeding unit.
The sheet feeding portion 100 is provided in a manner drawable in a
drawing direction orthogonal to a sheet feeding direction with
respect to an apparatus main body 200A and includes a storage 106
which stores a sheet S and a feeding unit 10 which feeds the sheet
S from the storage 106 toward an image forming portion 20.
The storage 106 is provided with a tray 105 which can lift and
lower and a tray lifting and lowering plate 109 for lifting and
lowering the tray 105. Drive is transmitted to the tray lifting and
lowering plate 109 by a tray lifting and lowering motor and a drive
transmission portion, which are not shown, whereby the tray lifting
and lowering plate 109 rotates with a rotation center 109a as a
center and lifts up the tray 105. The tray 105 is configured to
rotate with a rotation center 105a as a center.
The feeding unit 10 has a pickup roller 102 which feeds the sheet
inside the storage 106 and a feed roller 107 which feeds the sheet
fed by the pickup roller 102. In addition, the feeding unit 10 has
a retard roller 108 as a separation member which forms a separation
nip together with the feed roller 107 to separate sheets one by one
and conveying guides 400, 600, and 700 which guide the sheet to the
separation nip. In the vicinity of the pickup roller 102, a
detection sensor 110 for detecting a height (position) of a sheet
surface St of an uppermost sheet of sheets S stacked on the tray
105 is located. It is to be noted that although in the present
embodiment, the retard roller 108 is described as one example of
the separation member, the present invention is not limited
thereto, and for example, a separation pad can also be applied as
the separation member.
The feed roller 107 is supported by one end of a driving shaft 117,
in a detachably attachable manner, whose other end is supported by
a feeding frame 119 provided in the apparatus main body 200A. The
pickup roller 102 is located on a further upstream side than the
feed roller 107 in the sheet feeding direction. The pickup roller
102 is supported by, in a detachably attachable manner, one end
side of a supporting shaft 121 supported by the lifting and
lowering plate 111. The lifting and lowering plate 111 is supported
by the driving shaft 117 which supports the feed roller 107. In
addition, the lifting and lowering plate 111 has a second guide
member 600 as a conveying guide which guides a sheet fed from the
pickup roller 102 to the separation nip. The retard roller 108 as
the one example of the separation member is located in a position
facing the feed roller 107 and forms the separation nip together
with the feed roller 107. When a plurality of sheets is fed by the
pickup roller 102, the retard roller 108 separates the sheets one
by one together with the feed roller 107.
The first guide member 400 which constitutes the conveying guide is
located between the pickup roller 102 and the feed roller 107 in a
conveying direction and is located on a further downstream side
than the pickup roller 102, the feed roller 107, and the retard
roller 108 in the drawing direction of the storage 106. In other
words, the first guide member 400 is located in a position shifting
to a side of the drawing direction of the cassette 106 from the
rollers 102, 107, and 108. The first guide member 400 is configured
to be slidable in the drawing direction in an internal space of the
apparatus main body from which the storage 106 is drawn out, in
order to detach the pickup roller 102 and the feed roller 107 from
the driving shaft 117. As shown in FIG. 4, the first guide member
400 has a guide portion 400a which has a guiding surface guiding
the conveyed sheet to the separation nip and is a portion rubbed
with the sheet and a handle portion 400b operated by a user. In
addition, as shown in FIG. 12, hook portions 400c provided for the
first guide member 400 are supported by slide holes 119b provided
for the feeding frame 119 of the feeding unit 10. The slide holes
119b are extended in an axial direction of the feed roller 107, and
the first guide member 400 is slidably movable in the axial
direction by an opening width of each of the slide holes 119b with
respect to the feeding frame 119. The first guide member 400 is
slid from a guide position shown in FIG. 3 to a retract position
shown in FIG. 4, whereby a space (space 501 shown in FIG. 11C) is
formed between the first guide member 400 and the rollers and it is
made possible to replace the rollers (the feed roller 107 and the
pickup roller 102). It is to be noted that in the present
embodiment, the first guide member 400 is configured to be slidable
with respect to the feeding frame 119. However, the present
invention is not limited to this, and for example, the first guide
member 400 may be configured to be detachably attachable with
respect to the feeding frame 119. In addition, in order to enhance
visibility of the rollers 102 and 107, the first guide member 400
is formed of acrylic resin whose light transmittance of light
having a wavelength of 360 nm to 420 nm is 80% or more.
In addition, as shown in FIGS. 3, 4, and 9, the sheet feeding
portion 100 is provided with the second guide member 600 and the
third guide member 700, each of which constitutes the conveying
guide for guiding the sheet picked up by the pickup roller 102 to
the separation nip. Unlike the first guide member 400, the second
guide member 600 and the third guide member 700 are fixed to the
feeding frame 119.
The second guide member 600 is a guide member which is located
further above than the separation nip in a vertical direction and
is located upstream in the drawing direction of the cassette 106.
The third guide member 700 is a guide member which is located
further below than the separation nip in the vertical direction.
When the feed roller 107 is viewed from a space 500 (see FIG. 11B)
formed by drawing out the cassette 106, the second guide member 600
and the third guide member 700 are located in positions where the
second guide member 600 and the third guide member 700 do not
overlap with the feed roller 107. Since the second guide member 600
and the third guide member 700 exert less influence on the
visibility of the rollers than the first guide member 400 exerts
thereon, the second guide member 600 and the third guide member 700
are not required to be formed of a transparent resin material.
Therefore, in the present embodiment, the second guide member 600
and the third guide member 700 are formed of a resin material whose
light transmittance of the light having the wavelength of 360 nm to
420 nm is less than 80%. For example, the second guide member 600
and the third guide member 700 are formed of synthetic resin such
as ABS resin, which is a comparatively inexpensive material.
[Cassette]
With reference to FIGS. 5, 6, 7, and 8, a configuration of a
cassette 106 in a sheet feeding portion 100 will be described
further in detail. FIGS. 5, 6, and 7 are top views showing the
sheet feeding portion, viewed from an arrow B direction shown in
FIG. 2. FIG. 8 is a side view showing a part of the sheet feeding
portion, viewed from an arrow E direction shown in FIG. 1, and is
also a view showing a state in which the cassette 106 is supported
in the image forming apparatus.
The cassette 106 is provided with side end regulating plates 104F
and 104R and a rear end regulating plate 120 for regulating a
position of the sheet S set on the tray 105 in a movable manner.
The side end regulating plates 104F and 104R are provided in a
movable manner in a width direction orthogonal to the feeding
direction of the sheet. The rear end regulating plate 120 is
provided in a movable manner in the feeding direction of the sheet.
Accordingly, in accordance with a size of the sheet stored in the
cassette 106, the side end regulating plates 104F and 104R are
moved in the width direction, whereby positions of end portions of
the sheet in the width direction can be regulated by the side end
regulating plates 104F and 104R, and the rear end regulating plate
120 is moved in the feeding direction, whereby a position of an end
portion of the sheet on an upstream side in the feeding direction
can be regulated by the rear end regulating plate 120.
In addition, the cassette 106 is provided with a cassette rail 106b
such that the cassette 106 is supported in a drawable manner with
respect to the apparatus main body 200A. The cassette rail 106b is
provided with a rail roller 106c in a rotatable manner. In
addition, the apparatus main body 200A of the image forming
apparatus 200 is provided with a pair of supporting rails 300a and
300a such that the top and bottom of the cassette rail 106b
provided for the cassette 106 are sandwiched between the pair of
supporting rails 300a and 300a. The supporting rail 300a of the
pair of supporting rails 300a and 300a, which is located on a lower
side of the rail 106b, is provided with a supporting rail roller
300b in a rotatable manner, which contacts a lower surface of the
cassette rail 106b and rotates. The rail roller 106c provided for
the cassette rail 106b contacts the storage supporting rail 300a of
the pair of supporting rails 300a and 300a in a rotatable manner,
which is located on an upper side of the cassette rail 106b. The
cassette rail 106b is sandwiched between the pair of storage
supporting rails 300a and 300a, whereby the cassette 106 is
supported to the apparatus main body 200A of the image forming
apparatus 200 in the drawable manner. The cassette rail 106b and
the pair of storage supporting rails 300a and 300a are provided
along an axial direction of the driving shaft 117 which supports
the feed roller 107. Accordingly, the cassette 106 is provided in a
manner drawable in the axial direction of the driving shaft 117 of
the feed roller 107 with respect to the apparatus main body
200A.
As shown in FIG. 5, upon forming an image, the cassette 106 is
stored inside the apparatus main body 200A of the image forming
apparatus 200. When the sheet S is set inside the cassette 106, the
cassette 106 is drawn out in an arrow Y direction from the
apparatus main body 200A and is moved to a sheet setting position
shown in FIG. 6. At this time, the rail roller 106c provided for
the cassette rail 106b contacts the storage supporting rail 300a
located on the upper side and is rotated, and the storage
supporting rail roller 300b provided for the storage supporting
rail 300a located on the lower side contacts the cassette rail 106b
and is rotated. Thus, the cassette 106 is drawn out with low
resistance against the apparatus main body 200A and is moved to the
sheet setting position shown in FIG. 6. When the cassette 106 is
further drawn out from the apparatus main body 200A, as shown in
FIG. 7, the cassette 106 can be detached from the apparatus main
body 200A of the image forming apparatus. In addition, inside the
apparatus main body 200A of the image forming apparatus, a storage
detection sensor 103 which detects whether the cassette 106 is
stored inside the apparatus main body 200A is disposed.
[Feeding Unit]
Next, with reference to FIGS. 2, 3, and 9, a configuration and
operation of the feeding unit which includes the pickup roller 102,
the feed roller 107, and the retard roller 108 will be described
further in detail. FIG. 9 is a perspective view showing a
configuration of the vicinity of the rollers in the feeding
unit.
A driving force (rotating force) is transmitted to the driving
shaft 117 by a feeding driving motor and the drive transmission
portion, which are not shown, whereby the feed roller 107 is
rotated in a direction in which a sheet is fed. The retard roller
108 is pressed against the feed roller 107, thereby forming a
separation nip. The retard roller 108 receives a torque in a
direction opposite to a sheet feeding direction via a torque
limiter, not shown. A torque value of this torque limiter is set to
be larger than a value of a frictional force between a sheet and a
sheet and smaller than a value of a frictional force between the
sheet and the feed roller 107. Thus, when the number of the sheet
entering the separation nip between the feed roller 107 and the
retard roller 108 is one or no sheet enters the separation nip
therebetween, the retard roller 108 is co-rotated with the feed
roller 107. On the other hand, when the number of sheets entering
the separation nip between the feed roller 107 and the retard
roller 108 is two or more, a force in the direction opposite to the
feeding direction is exerted on the retard roller 108 due to
working of the torque limiter, thereby separating the sheets one by
one. In other words, when a plurality of sheets is fed by the
pickup roller 102, the retard roller 108 separates one sheet from
the other sheets contacting the feed roller 107.
In addition, an idler gear 114 is supported to the driving shaft
117 of the feed roller 107. The rotating force transmitted to the
driving shaft 117 of the feed roller 107 rotates the idler gear 114
which rotates in conjunction with the driving shaft 117. The
lifting and lowering plate 111 is supported to the driving shaft
117 in a rotatable (swingable) manner. Although the description is
given later, the supporting shaft 121 which supports the pickup
roller 102 in a rotatable manner is supported to the lifting and
lowering plate 111, and the pickup roller 102 is supported by the
lifting and lowering plate 111 in a rotatable (swingable) manner
with the driving shaft 117 as a center. In addition, the lifting
and lowering plate 111 is provided with an idler shaft 113A which
supports an idler gear 113 which engages with the idler gear 114
supported to the driving shaft 117. Furthermore, the supporting
shaft 121 which supports the pickup roller 102 is supported to the
lifting and lowering plate 111 as described above. An idler gear
112 which engages with the idler gear 113 is supported to the
supporting shaft 121 of the pickup roller 102. Accordingly, the
rotating force transmitted to the driving shaft 117 of the feed
roller 107 from the feeding driving motor, not shown, is
transmitted to the idler gear 114 and is further transmitted via
the idler gear 113 to the idler gear 112. The rotating force
transmitted to the idler gear 112 is transmitted from the idler
gear 112 to the pickup roller 102 by a coupling mechanism 112A and
rotates the pickup roller 102. The driving force (rotating force)
is transmitted to the pair of conveying rollers 11 located
downstream of the feed roller 107 by a conveyance driving motor and
the drive transmission portion, which are not shown, whereby the
pair of conveying rollers 11 are rotated in the direction in which
the sheet is conveyed.
[Configuration of Attachment and Detachment of Rollers]
Next, with reference to FIGS. 9 and 10, a configuration of
attachment and detachment of rollers of a feeding unit will be
described. A pickup roller 102, a feed roller 107, and a retard
roller 108 which constitute the feeding unit 10 are provided in a
detachably attachable manner to the apparatus main body 200A. Here,
as an example, the feed roller 107 will be described in an
illustrative manner. FIGS. 10A and 10B are cross-sectional views
showing the feed roller 107.
On a peripheral surface of an end portion on the other end side of
a driving shaft 117 which is a supporting shaft of the feed roller
107, an engaging groove 117A which is a groove portion is formed.
The feed roller 107 is constituted of a core portion 107A which is
formed of resin and an outer peripheral portion 107B which is
provided on an outer side of the core portion 107A, is formed of
rubber, and abuts against a sheet S. The core portion 107A has an
engaging projection 107a, a disengaging portion 107b, and a handle
portion 107c. Here, the core portion 107A is an integrally molded
component, having the engaging projection 107a, the disengaging
portion 107b, and the handle portion 107c. The disengaging portion
107b is provided with the engaging projection 107a which is
engageable or disengageable with the engaging groove 117A when the
engaging projection 107a is elastically deformed by a user. The
disengaging portion 107b is provided in such a way as to extend
from the engaging projection 107a toward the other end side of the
driving shaft 117. The handle portion 107c is provided on a further
outer side than the engaging projection 107a with respect to a
rotation center of the feed roller 107. Accordingly, with the
engaging projection 107a of the core portion 107A engaged with the
engaging groove 117A of the driving shaft 117, the feed roller 107
is inhibited from slipping out of the driving shaft 117. On the
other hand, for example, in a state in which a user presses the
handle portion 107c with his or her one finger, the user
elastically deforms the disengaging portion 107b toward an outer
side in a radial direction with his or her other finger, whereby
the engagement of the engaging projection 107a with the engaging
groove 117A is disengaged and the feed roller 107 can be detached
from the driving shaft 117. It is to be noted that since a
configuration in which each of the pickup roller 102 and the retard
roller 108 is detached is the same as the configuration in which
the feed roller 107 is detached, description therefor is
omitted.
Next, with reference to FIGS. 11 and 13, a configuration, in which
each roller is replaced, characterizes the present embodiment will
be described. FIGS. 11A, 11B, and 11C are cross-sectional views
showing a state of the cassette 106 and the feeding unit 10, viewed
from an arrow C direction shown in FIG. 2. FIG. 13 is a view
showing the vicinity of the rollers of the feeding unit in a space,
viewed from an arrow D direction in FIG. 11B.
A user draws the cassette 106 from the apparatus main body 200A of
the image forming apparatus, thereby changing a state shown in FIG.
11A to a state shown in FIG. 11B. Hereupon, each of the rollers of
the feeding unit 10 comes to be accessible from an internal space
500 of the apparatus main body, which is formed by drawing the
cassette 106 therefrom.
As shown in FIG. 13, in order to prevent failure in sheet feeding
such as turning-up of a leading edge of a sheet caused when the
sheet runs into the feed roller 107, a distance d between the first
guide member 400 and a position of the nip formed between the feed
roller 107 and the retard roller 108 is made small. Therefore, when
the internal space 500 of the apparatus main body 200A is viewed
from a side on which the cassette 106 is drawn out, in particular,
a large part (at least half or more of area) of the feed roller 107
is in positional relationship in which the large part thereof is
hidden by the first guide member 400. Therefore, in the present
embodiment, as described above, as the material of the first guide
member 400, the transparent acrylic resin is used. This material
has the property which is the light transmittance of light having
the wavelength of 360 nm to 420 nm is 80% or more. Thus, when a
user views the internal space 500 of the apparatus main body 200A
from the side on which the cassette 106 is drawn out, even when the
first guide member 400 is present in front of the feed roller 107,
the whole of the feed roller 107 is easily viewed through the
transparent first guide member 400.
In addition, color of each of the engaging projection 107a, the
disengaging portion 107b, and the handle portion 107c (see FIG. 10)
provided for the core portion of the feed roller 107 is different
from color of the feeding frame 119 of the feeding unit 10 included
in the apparatus main body. In the present embodiment, the feeding
frame 119 is formed of synthetic resin material such as ABS resin,
whose color is black and light transmittance of light having a
wavelength of at least 360 nm to 420 nm is less than 80%. Each of
the engaging projection 107a, the disengaging portion 107b, and the
handle portion 107c provided for the core portion of the feed
roller 107 is formed of a resin material whose color is white.
Thus, each of the rollers, which is required to be replaced, can be
made conspicuous as contrasted with the feeding frame 119, thereby
further enhancing visibility.
As described above, according to the present embodiment, the first
guide member 400 is formed of the acrylic resin material whose
light transmittance of the light having the wavelength of 360 nm to
420 nm is 80% or more. Therefore, after drawing out the cassette
106 from the apparatus main body 200A, each of the rollers (such as
the pickup roller 102 and the feed roller 108) which is targeted
for replacement can be easily visually recognized. After the roller
to be replaced has been visually recognized, as shown in FIG. 11C,
the first guide member 400 is drawn in an arrow F direction,
thereby allowing the space 501 required to attach or detach the
roller to be ensured.
In addition, in the present embodiment, the example in which the
first guide member 400 is formed of the transparent resin material
is described. However, the first guide member 400 may be formed of
two members which are a transparent resin material and a
non-transparent resin material. For example, only the guide portion
400a of the first guide member 400 may be formed of the acrylic
resin which is the transparent resin material, and the handle
portion 400b grasped upon sliding the first guide member 400 may be
formed of the non-transparent resin material. The guide portion
400a and the handle portion 400b are formed as described above,
thereby enhancing the visibility of the rollers and allowing a
position of the handle portion 400b, which does not influence the
visibility of the rollers, to be made conspicuous. In addition,
only portions of the guide portion 400a, which are close to the
rollers 102 and 107, may be formed of the transparent resin
material, and a portion of the guide portion 400a, which is close
to the handle portion 400b, may be formed of the non-transparent
resin material.
In addition, both or at least one of the core portion 107A and the
outer peripheral portion 107B of the feed roller 107 are or is
formed of a material having chromatic color, thereby also allowing
the visibility of the rollers to be enhanced.
In addition, although in the embodiment descried hereinbefore, as
the image forming apparatus, the printer is illustrated as the
example, the present invention is not limited to this. For example,
the image forming apparatus may be other image forming apparatus
such as a copying machine and a facsimile apparatus or may be other
image forming apparatus such as a multifunction machine having the
above-mentioned functions combined therein. In addition, although
the image forming apparatus in which the intermediate transfer
member is used, the toner images having the respective colors are
transferred to the intermediate transfer member in a sequentially
superimposed manner, and the toner images carried on the
intermediate transfer member are collectively transferred to the
sheet is illustrated as the example, the present invention is not
limited to this. The image forming apparatus according thereto may
be an image forming apparatus in which a sheet carrier is used and
the toner images having the respective colors are transferred in a
sequentially superimposed manner onto a sheet carried on the sheet
carrier. The present invention is applied to a sheet feeding device
used in each of these image forming apparatuses, thereby allowing
similar effects to be obtained.
While the present invention has been described with reference to
exemplary embodiments, it is to be understood that the invention is
not limited to the disclosed exemplary embodiments. The scope of
the following claims is to be accorded the broadest interpretation
so as to encompass all such modifications and equivalent structures
and functions.
This application claims the benefit of Japanese Patent Application
No. 2019-161729, filed Sep. 5, 2019, which is hereby incorporated
by reference herein in its entirety.
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